Phase II studies are therapeutic investigations of new agents that have finished Phase I testing (i.e. clinical toxicology and pharmacology studies). Completed negative Phase II trials have been done with 6-thioguanine in colorectal carcinoma and Methly-G in renal cell carcinoma. Trials are currently underway with Methyl-G in GU tumors and esophageal carcinoma, DHAD, in soft tissue sarcomae, AMSA in malignant melanoma, AZQ in oat cell carcinoma of the lung and head and neck malignancies; and neocarzinostatin plus VP16-213 in hepatocellular carcinoma.